Chapter 5: Problem 19
A model of a spring/mass system is \(4 x^{\prime \prime}+e^{-0.1 t} x=0 .\) By inspection of the differential equation only, discuss the behavior of the system over a long period of time.
Short Answer
Expert verified
The system's damping effect diminishes over time, leading to undamped-like behavior long-term.
Step by step solution
01
Identify the Differential Equation Type
The given differential equation is \(4 x'' + e^{-0.1t} x = 0\). This is a second-order linear differential equation with a variable coefficient, \(e^{-0.1t}\), in the damping term.
02
Analyze the Damping Term
The damping term is \(e^{-0.1t} x\). As time, \(t\), increases, the term \(e^{-0.1t}\) decays exponentially to zero. This indicates that the damping effect diminishes over time.
03
Discuss the Implications for Long-term Behavior
Since the damping term \(e^{-0.1t} x\) becomes negligible as \(t\to\infty\), the damping effect decreases. Therefore, over a long period, the behavior of the system is influenced less by damping, and the motion approaches that of an undamped system.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Spring-Mass System
The spring-mass system is a fundamental concept in physics involving a mass attached to a spring. This system demonstrates how objects move when subjected to forces. In essence, a spring-mass system consists of:
- A mass, which is the object being moved or oscillated, and
- A spring, which provides the restoring force to bring the mass back to its equilibrium position.
Damping
Damping refers to the reduction of motion in a system, usually caused by resistive forces like friction. In a spring-mass system, damping is critical because it affects the oscillation's amplitude over time. In the context of the equation given, the damping term is expressed by the variable coefficient, \(e^{-0.1t}\), which multiplies the position function \(x\).
- This exponential term represents the damping effect on the system.
- As time \(t\) increases, \(e^{-0.1t}\) decays exponentially towards zero.
Second-Order Linear Differential Equation
A second-order linear differential equation is a mathematical tool used to describe systems involving acceleration, such as spring-mass systems. In our case, the equation \(4 x'' + e^{-0.1t} x = 0\) is a second-order linear differential equation because it involves the second derivative of \(x\), the position.
- The second-order nature refers to the highest derivative being the second derivative (\(x''\)).
- A linear differential equation implies that the function and its derivatives are linear.
Exponential Decay
Exponential decay describes a process where a quantity decreases at a rate proportional to its current value. This concept is central to the term \(e^{-0.1t}\) in the given differential equation, acting as a damping factor.
- Here, \(e^{-0.1t}\) highlights how the system's damping force fades over time.
- The term \(e^{-0.1t}\) indicates that for each unit increase in time \(t\), the factor decreases by a consistent percentage.